Keyless access control systems are becoming more common. Rather than carrying keys, possibly many keys in the case of, for example, the various locks in an office building, such keyless systems allow a user to carry a single item or “credential,” for example, a keycard, fob or other remote device (all referred to herein as “remote device”), that permits access to one or more locations. The user may more quickly gain access to an area without the need to find, insert and turn a traditional key in a lock if they carry a credential granting authorization to that area.
The credential carried by the user is characterized depending upon whether it contains a battery or does not contain a battery. A credential is considered to be “active” if it contains a battery, and “passive” if it does not contain a battery.
Prior art keyless locks generally operate in one of two ways. In a first type of keyless lock system, a “capacitive touch” system, a user carries an active credential that transmits a wireless signal, typically a Bluetooth signal, which is coded to indicate which location(s) the user should have access to, i.e., which locks may be unlocked. The user touches a lock which causes a change in measured capacitance, which in turn causes a sensor to search for a received Bluetooth signal from the active credential that indicates authorization to unlock the lock and allow the user to enter the location secured by the lock. If the Bluetooth signal from the user's active credential indicates such authorization, the lock is unlocked.
The range of such an active credential is preferably great enough that the user may keep the active credential in a pocket or purse while the user touches the lock. The active credential may be contained in a remote device that may, for example, be located on a keychain, or may be located within a mobile device such as a smartphone. One example of this type of keyless lock is the Kwikset Kevo from Spectrum Brands, Inc. of Middleton, Wis.
In some systems, the user need not actually touch a sensor to begin the access process, but rather a sensor may either detect the Bluetooth signal from the active credential based on the physically close presence of the active credential, for example, within about 12 inches of the sensor, or may even be able to detect a wave of the user's hand near the sensor. In the following discussion, references that the user touches a capacitive touch sensor to initiate the process are intended to include such systems that work based upon proximity as well.
In another type of keyless lock, commonly known as a radio-frequency identification (“RFID”) system, the user carries a passive credential, which again may be a keycard, fob or other remote device (again all referred to as “remote device”), that typically contains an RFID chip that contains a passive tag with an authorization code that indicates which location(s) the user should have access to as well as, if desired, a card number. A card “reader” is mounted near the lock, and an antenna within the reader constantly generates an excitation signal.
When the RFID remote device is presented close enough to the reader, typically within about 5 centimeters of the reader, the excitation signal provides energy to the passive tag through inductive coupling, thus energizing the tag to wirelessly send its authorization code to the reader. The code is then passed to a controller, in some embodiments using the industry standard Wiegand communications protocol. If the authorization code is appropriate for the lock connected to the reader, the controller causes the lock to be unlocked.
Both capacitive touch systems and RFID systems are able to operate in a rapid fashion, so that the user does not experience a significant delay in opening a lock and gaining needed physical access when authorized. Detection of the Bluetooth signal, or the remote device code, is typically obtained in a fraction of a second, although the determination of whether the user is authorized to enter a location and unlocking of the lock may take a bit longer.
Until now it has not been thought possible to combine the two types of keyless locks to operate a single lock. RFID readers typically constantly generate an excitation signal at either 125 kilohertz (KHz) or 13.56 megahertz (MHz). When trying to integrate a capacitive touch sensor into an RFID reader, however, it has been found that the RFID excitation signal also energizes the capacitive touch sensor so that, when touched, the measured capacitance does not change enough to indicate that a user has touched the sensor. Thus, the capacitive touch sensor is essentially inoperable in this situation.
Accordingly, it would be desirable to have an improved keyless lock system that is capable of incorporating both a capacitive touch sensor with active credential, and an RFID sensor with passive credential.